Related: tdf#74299: use OEM encoding for ancient DXF

This patch analyses DXF version data to heuristically detect
which files use OEM text encoding (DOS versions of AutoCAD).
Also, it uses LO's currently-selected default document language,
instead of system locale, so that user can change that to match
language of the DXF, and get correct result.

Change-Id: I3aec7e24f3d7efca35d0dd1acca8b277a076f210
Reviewed-on: https://gerrit.libreoffice.org/28556
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>

3 files changed, 98 insertions, 48 deletions

diff --git a/filter/Library_gie.mk b/filter/Library_gie.mk
index d39504b23495..2c00c75e2ea6 100644
--- a/filter/Library_gie.mk
+++ b/filter/Library_gie.mk
@@ -23,46 +23,50 @@ $(eval $(call gb_Library_use_external,gie,boost_headers))
 
 $(eval $(call gb_Library_use_sdk_api,gie))
 
+$(eval $(call gb_Library_use_custom_headers,gie,\
+	officecfg/registry \
+))
+
 $(eval $(call gb_Library_use_libraries,gie,\
-	basegfx \
+    basegfx \
     comphelper \
     i18nlangtag \
     svt \
-	vcl \
+    vcl \
     utl \
-	tl \
+    tl \
     tk \
-	cppu \
-	sal \
-	$(gb_UWINAPI) \
+    cppu \
+    sal \
+    $(gb_UWINAPI) \
 ))
 
 $(eval $(call gb_Library_add_exception_objects,gie,\
-	filter/source/graphicfilter/egif/egif \
-	filter/source/graphicfilter/etiff/etiff \
-	filter/source/graphicfilter/eps/eps \
-	filter/source/graphicfilter/egif/giflzwc \
-	filter/source/graphicfilter/itiff/ccidecom \
-	filter/source/graphicfilter/itiff/itiff \
-	filter/source/graphicfilter/itiff/lzwdecom \
-	filter/source/graphicfilter/ipict/ipict \
-	filter/source/graphicfilter/ipict/shape \
-	filter/source/graphicfilter/ipcx/ipcx \
-	filter/source/graphicfilter/iras/iras \
-	filter/source/graphicfilter/itga/itga \
-	filter/source/graphicfilter/ieps/ieps \
-	filter/source/graphicfilter/ipsd/ipsd \
-	filter/source/graphicfilter/ipbm/ipbm \
-	filter/source/graphicfilter/ios2met/ios2met \
-	filter/source/graphicfilter/idxf/dxf2mtf \
-	filter/source/graphicfilter/idxf/dxfblkrd \
-	filter/source/graphicfilter/idxf/dxfentrd \
-	filter/source/graphicfilter/idxf/dxfgrprd \
-	filter/source/graphicfilter/idxf/dxfreprd \
-	filter/source/graphicfilter/idxf/dxftblrd \
-	filter/source/graphicfilter/idxf/dxfvec \
-	filter/source/graphicfilter/idxf/idxf \
-	filter/source/graphicfilter/ipcd/ipcd \
+    filter/source/graphicfilter/egif/egif \
+    filter/source/graphicfilter/etiff/etiff \
+    filter/source/graphicfilter/eps/eps \
+    filter/source/graphicfilter/egif/giflzwc \
+    filter/source/graphicfilter/itiff/ccidecom \
+    filter/source/graphicfilter/itiff/itiff \
+    filter/source/graphicfilter/itiff/lzwdecom \
+    filter/source/graphicfilter/ipict/ipict \
+    filter/source/graphicfilter/ipict/shape \
+    filter/source/graphicfilter/ipcx/ipcx \
+    filter/source/graphicfilter/iras/iras \
+    filter/source/graphicfilter/itga/itga \
+    filter/source/graphicfilter/ieps/ieps \
+    filter/source/graphicfilter/ipsd/ipsd \
+    filter/source/graphicfilter/ipbm/ipbm \
+    filter/source/graphicfilter/ios2met/ios2met \
+    filter/source/graphicfilter/idxf/dxf2mtf \
+    filter/source/graphicfilter/idxf/dxfblkrd \
+    filter/source/graphicfilter/idxf/dxfentrd \
+    filter/source/graphicfilter/idxf/dxfgrprd \
+    filter/source/graphicfilter/idxf/dxfreprd \
+    filter/source/graphicfilter/idxf/dxftblrd \
+    filter/source/graphicfilter/idxf/dxfvec \
+    filter/source/graphicfilter/idxf/idxf \
+    filter/source/graphicfilter/ipcd/ipcd \
 ))
 
 # vim: set noet sw=4 ts=4:
diff --git a/filter/source/graphicfilter/idxf/dxfreprd.cxx b/filter/source/graphicfilter/idxf/dxfreprd.cxx
index 6a80a9686db6..838e2702bffe 100644
--- a/filter/source/graphicfilter/idxf/dxfreprd.cxx
+++ b/filter/source/graphicfilter/idxf/dxfreprd.cxx
@@ -19,8 +19,11 @@
 
 
 #include <string.h>
-#include <dxfreprd.hxx>
+#include "dxfreprd.hxx"
 #include "osl/nlsupport.h"
+#include "officecfg/Setup.hxx"
+#include "officecfg/Office/Linguistic.hxx"
+#include "unotools/wincodepage.hxx"
 
 //------------------DXFBoundingBox--------------------------------------------
 
@@ -128,9 +131,8 @@ void DXFPalette::SetColor(sal_uInt8 nIndex, sal_uInt8 nRed, sal_uInt8 nGreen, sa
 
 
 DXFRepresentation::DXFRepresentation()
-    : bUseUTF8(false)
+    : mEnc(RTL_TEXTENCODING_DONTKNOW)
 {
-    setTextEncoding(osl_getTextEncodingFromLocale(nullptr)); // Use default encoding if none specified
     setGlobalLineTypeScale(1.0);
 }
 
@@ -139,6 +141,24 @@ DXFRepresentation::~DXFRepresentation()
 {
 }
 
+namespace {
+
+OUString getLODefaultLanguage()
+{
+    OUString result(officecfg::Office::Linguistic::General::DefaultLocale::get());
+    if (result.isEmpty())
+        result = officecfg::Setup::L10N::ooSetupSystemLocale::get();
+    return result;
+}
+
+}
+
+rtl_TextEncoding DXFRepresentation::getTextEncoding() const
+{
+    return (isTextEncodingSet()) ?
+        mEnc :
+        osl_getTextEncodingFromLocale(nullptr); // Use default encoding if none specified
+}
 
 bool DXFRepresentation::Read( SvStream & rIStream, sal_uInt16 /*nMinPercent*/, sal_uInt16 /*nMaxPercent*/)
 {
@@ -196,18 +216,48 @@ void DXFRepresentation::ReadHeader(DXFGroupReader & rDGR)
             {
                 if (!rDGR.Read(1))
                     continue;
-                if (rDGR.GetS() >= "AC1021")
-                    bUseUTF8 = true;
+                // Versions of AutoCAD up to Release 12 (inclusive, AC1009)
+                // were DOS software and used OEM encoding for storing strings.
+                // Release 13 (AC1012) had both DOS and Windows variants.
+                // Its Windows variant, and later releases used ANSI encodings for
+                // strings (up to version 2006, which was the last one to do so).
+                // Later versions (2007+, AC1021+) use UTF-8 for that.
+                // Other (non-Autodesk) implementations may have used different
+                // encodings for storing to corresponding formats, but there's
+                // no way to know that.
+                // See http://autodesk.blogs.com/between_the_lines/autocad-release-history.html
+                if ((rDGR.GetS() <= "AC1009") || (rDGR.GetS() == "AC2.22") || (rDGR.GetS() == "AC2.21") || (rDGR.GetS() == "AC2.10") ||
+                    (rDGR.GetS() == "AC1.50") || (rDGR.GetS() == "AC1.40") || (rDGR.GetS() == "AC1.2")  || (rDGR.GetS() == "MC0.0"))
+                {
+                    // Set OEM encoding for old DOS formats
+                    // only if the encoding is not set yet
+                    // e.g. by previous $DWGCODEPAGE
+                    if (!isTextEncodingSet())
+                        setTextEncoding(utl_getWinTextEncodingFromLangStr(getLODefaultLanguage().toUtf8().getStr(), true));
+                }
+                else if (rDGR.GetS() >= "AC1021")
+                    setTextEncoding(RTL_TEXTENCODING_UTF8);
+                else
+                {
+                    // Set ANSI encoding for old Windows formats
+                    // only if the encoding is not set yet
+                    // e.g. by previous $DWGCODEPAGE
+                    if (!isTextEncodingSet())
+                        setTextEncoding(utl_getWinTextEncodingFromLangStr(getLODefaultLanguage().toUtf8().getStr()));
+                }
             }
             else if (rDGR.GetS() == "$DWGCODEPAGE")
             {
                 if (!rDGR.Read(3))
                     continue;
 
+                // If we already use UTF8, then don't update encoding anymore
+                if (isTextEncodingUTF8())
+                    continue;
                 // FIXME: we really need a whole table of
                 // $DWGCODEPAGE to encodings mappings
-                if ( (rDGR.GetS().equalsIgnoreAsciiCase("ANSI_932")) ||
-                     (rDGR.GetS().equalsIgnoreAsciiCase("DOS932")) )
+                else if ( (rDGR.GetS().equalsIgnoreAsciiCase("ANSI_932")) ||
+                          (rDGR.GetS().equalsIgnoreAsciiCase("DOS932")) )
                 {
                     setTextEncoding(RTL_TEXTENCODING_MS_932);
                 }
diff --git a/filter/source/graphicfilter/idxf/dxfreprd.hxx b/filter/source/graphicfilter/idxf/dxfreprd.hxx
index a7ad7531f975..66cc747b41cd 100644
--- a/filter/source/graphicfilter/idxf/dxfreprd.hxx
+++ b/filter/source/graphicfilter/idxf/dxfreprd.hxx
@@ -90,28 +90,28 @@ public:
 
     rtl_TextEncoding mEnc;  // $DWGCODEPAGE
 
-    bool bUseUTF8; // for AC1021 and higher
-
     double mfGlobalLineTypeScale; // $LTSCALE
 
     DXFRepresentation();
     ~DXFRepresentation();
 
     rtl_TextEncoding getTextEncoding() const;
-    void setTextEncoding(rtl_TextEncoding aEnc);
+    void setTextEncoding(rtl_TextEncoding aEnc) { mEnc = aEnc; }
     OUString ToOUString(const OString& s) const;
 
-    double getGlobalLineTypeScale() const;
-    void setGlobalLineTypeScale(double fGlobalLineTypeScale);
+    double getGlobalLineTypeScale() const { return mfGlobalLineTypeScale; }
+    void setGlobalLineTypeScale(double fGlobalLineTypeScale) { mfGlobalLineTypeScale = fGlobalLineTypeScale; }
 
     bool Read( SvStream & rIStream, sal_uInt16 nMinPercent, sal_uInt16 nMaxPercent);
         // Reads complete DXF file.
 
 private:
-
     void ReadHeader(DXFGroupReader & rDGR);
     void CalcBoundingBox(const DXFEntities & rEntities,
                          DXFBoundingBox & rBox);
+
+    bool isTextEncodingSet() const { return mEnc != RTL_TEXTENCODING_DONTKNOW; }
+    bool isTextEncodingUTF8() const { return mEnc == RTL_TEXTENCODING_UTF8; }
 };
 
 
@@ -121,10 +121,6 @@ private:
 inline sal_uInt8 DXFPalette::GetRed(sal_uInt8 nIndex) const { return pRed[nIndex]; }
 inline sal_uInt8 DXFPalette::GetGreen(sal_uInt8 nIndex) const { return pGreen[nIndex]; }
 inline sal_uInt8 DXFPalette::GetBlue(sal_uInt8 nIndex) const { return pBlue[nIndex]; }
-inline rtl_TextEncoding DXFRepresentation::getTextEncoding() const { return bUseUTF8 ? RTL_TEXTENCODING_UTF8 : mEnc; }
-inline void DXFRepresentation::setTextEncoding(rtl_TextEncoding aEnc) { mEnc = aEnc; }
-inline double DXFRepresentation::getGlobalLineTypeScale() const { return mfGlobalLineTypeScale; }
-inline void DXFRepresentation::setGlobalLineTypeScale(double fGlobalLineTypeScale) { mfGlobalLineTypeScale = fGlobalLineTypeScale; }
 
 #endif